Attachment or PDF Download Failed - Airmail for iOS

If Airmail for iPhone or iPad shows "Download failed" when you try to open a PDF or another attachment, the file could not be retrieved from your mail server. This usually happens after an app update, when the local cache for the account is out of date, or when the connection to the server is interrupted. Nothing is lost: the attachment is still safely stored on your mail server.

Follow the steps below in order and try opening the attachment again after each one.

Step 1 - Update Airmail
Open the App Store, search for Airmail and install any available update. Then close Airmail completely (swipe it away from the app switcher) and reopen it.

Step 2 - Check your connection and storage
Make sure the device is online (try opening a web page in Safari) and that it has enough free space: go to Settings > General > iPhone Storage. Large attachments cannot be downloaded if the device is almost full.

Step 3 - Open the message again
Go back to the message list, pull down to refresh, open the message and tap the attachment once more. If the attachment preview appears but the file does not open, tap the Share icon and choose Save to Files, or open it with another app such as Files or Books.

Step 4 - Re-add the account
If the download still fails, remove the account from Airmail and add it again. This clears the local cache for that account and downloads the messages and attachments fresh from the server. Open Airmail and go to Settings > Accounts, select the account and choose Remove account, then add the account again from Settings > Accounts > Add account. Your emails remain on the server; only the local copy on the device is rebuilt. Keep your account password or app-specific password at hand.

Still not working?
Contact us from the app (Settings > Support) or at airmailapp.com and include: the device model, the iOS version, the Airmail version (Settings > About), the type of account (Gmail, iCloud, Outlook, IMAP) and, if possible, the approximate size of the attachment. Our team will investigate and get back to you.

Updated on: 10/01/2026